org.apache.hadoop.hbase.client

类 ClientScanner

java.lang.Object

org.apache.hadoop.hbase.client.AbstractClientScanner

org.apache.hadoop.hbase.client.ClientScanner

所有已实现的接口:

Closeable, AutoCloseable, Iterable<Result>, ResultScanner

直接已知子类:

ClientSmallScanner, ReversedClientScanner

@InterfaceAudience.Private
public class ClientScanner
extends AbstractClientScanner

Implements the scanner interface for the HBase client. If there are multiple regions in a table, this scanner will iterate through them all.

字段概要

字段

限定符和类型	字段和说明
protected LinkedList<Result>	cache
protected int	caching
protected org.apache.hadoop.hbase.client.ScannerCallableWithReplicas	callable
protected RpcRetryingCaller<Result[]>	caller
protected boolean	closed
protected org.apache.hadoop.conf.Configuration	conf
protected HRegionInfo	currentRegion
protected long	lastNext
protected Result	lastResult
protected long	maxScannerResultSize
protected ExecutorService	pool
protected int	primaryOperationTimeout
protected RpcControllerFactory	rpcControllerFactory
protected Scan	scan
protected boolean	scanMetricsPublished
protected int	scannerTimeout

从类继承的字段 org.apache.hadoop.hbase.client.AbstractClientScanner

scanMetrics

构造器概要

构造器

构造器和说明
ClientScanner(org.apache.hadoop.conf.Configuration conf, Scan scan, org.apache.hadoop.hbase.TableName tableName, ClusterConnection connection, RpcRetryingCallerFactory rpcFactory, RpcControllerFactory controllerFactory, ExecutorService pool, int primaryOperationTimeout) Create a new ClientScanner for the specified table Note that the passed Scan's start row maybe changed changed.

方法概要

方法

限定符和类型	方法和说明
protected boolean	checkScanStopRow(byte[] endKey)
void	close() Closes the scanner and releases any resources it has allocated
int	getCacheSize()
protected int	getCaching()
protected org.apache.hadoop.conf.Configuration	getConf()
protected ClusterConnection	getConnection()
protected long	getMaxResultSize()
protected ExecutorService	getPool()
protected int	getPrimaryOperationTimeout()
protected int	getRetries()
protected Scan	getScan()
protected org.apache.hadoop.hbase.client.ScannerCallableWithReplicas	getScannerCallable(byte[] localStartKey, int nbRows)
protected int	getScannerTimeout()
protected org.apache.hadoop.hbase.TableName	getTable()
protected byte[]	getTableName() 已过时。 Since 0.96.0; use getTable()
protected long	getTimestamp()
protected void	initializeScannerInConstruction()
protected void	loadCache() Contact the servers to load more Results in the cache.
Result	next() Grab the next row's worth of values.
protected boolean	nextScanner(int nbRows, boolean done)
boolean	renewLease() Allow the client to renew the scanner's lease on the server.
protected void	writeScanMetrics() Publish the scan metrics.

从类继承的方法 org.apache.hadoop.hbase.client.AbstractClientScanner

getScanMetrics, initScanMetrics, iterator, next

从类继承的方法 java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

字段详细资料

scan

protected Scan scan

closed

protected boolean closed

currentRegion

protected HRegionInfo currentRegion

callable

protected org.apache.hadoop.hbase.client.ScannerCallableWithReplicas callable

cache

protected final LinkedList<Result> cache

caching

protected final int caching

lastNext

protected long lastNext

lastResult

protected Result lastResult

maxScannerResultSize

protected final long maxScannerResultSize

scannerTimeout

protected final int scannerTimeout

scanMetricsPublished

protected boolean scanMetricsPublished

caller

protected RpcRetryingCaller<Result[]> caller

rpcControllerFactory

protected RpcControllerFactory rpcControllerFactory

conf

protected org.apache.hadoop.conf.Configuration conf

primaryOperationTimeout

protected final int primaryOperationTimeout

pool

protected final ExecutorService pool

构造器详细资料

ClientScanner

public ClientScanner(org.apache.hadoop.conf.Configuration conf,
             Scan scan,
             org.apache.hadoop.hbase.TableName tableName,
             ClusterConnection connection,
             RpcRetryingCallerFactory rpcFactory,
             RpcControllerFactory controllerFactory,
             ExecutorService pool,
             int primaryOperationTimeout)
              throws IOException

Create a new ClientScanner for the specified table Note that the passed Scan's start row maybe changed changed.

参数:

conf - The Configuration to use.

scan - Scan to use in this scanner

tableName - The table that we wish to scan

connection - Connection identifying the cluster

抛出:

IOException

方法详细资料

initializeScannerInConstruction

protected void initializeScannerInConstruction()
                                        throws IOException

抛出:

IOException

getConnection

protected ClusterConnection getConnection()

getTableName

@Deprecated
protected byte[] getTableName()

已过时。 Since 0.96.0; use getTable()

返回:

Table name

getTable

protected org.apache.hadoop.hbase.TableName getTable()

getRetries

protected int getRetries()

getScannerTimeout

protected int getScannerTimeout()

getConf

protected org.apache.hadoop.conf.Configuration getConf()

getScan

protected Scan getScan()

getPool

protected ExecutorService getPool()

getPrimaryOperationTimeout

protected int getPrimaryOperationTimeout()

getCaching

protected int getCaching()

getTimestamp

protected long getTimestamp()

getMaxResultSize

protected long getMaxResultSize()

getCacheSize

public int getCacheSize()

checkScanStopRow

protected boolean checkScanStopRow(byte[] endKey)

nextScanner

protected boolean nextScanner(int nbRows,
                  boolean done)
                       throws IOException

抛出:

IOException

getScannerCallable

@InterfaceAudience.Private
protected org.apache.hadoop.hbase.client.ScannerCallableWithReplicas getScannerCallable(byte[] localStartKey,
                                                                                                      int nbRows)

writeScanMetrics

protected void writeScanMetrics()

Publish the scan metrics. For now, we use scan.setAttribute to pass the metrics back to the application or TableInputFormat.Later, we could push it to other systems. We don't use metrics framework because it doesn't support multi-instances of the same metrics on the same machine; for scan/map reduce scenarios, we will have multiple scans running at the same time. By default, scan metrics are disabled; if the application wants to collect them, this behavior can be turned on by calling calling Scan.setScanMetricsEnabled(boolean)

This invocation clears the scan metrics. Metrics are aggregated in the Scan instance.

next

public Result next()
            throws IOException

从接口复制的说明: ResultScanner

Grab the next row's worth of values. The scanner will return a Result.

返回:

Result object if there is another row, null if the scanner is exhausted.

抛出:

IOException - e

loadCache

protected void loadCache()
                  throws IOException

Contact the servers to load more Results in the cache.

抛出:

IOException

close

public void close()

从接口复制的说明: ResultScanner

Closes the scanner and releases any resources it has allocated

renewLease

public boolean renewLease()

从类复制的说明: AbstractClientScanner

Allow the client to renew the scanner's lease on the server.

指定者:

renewLease 在类中 AbstractClientScanner

返回:

true if the lease was successfully renewed, false otherwise.